Phenylbutyrate has been extensively used to treat patients with rare metabolic diseases (which are very different from CF), Phenylbutyrate is an investigational drug for the purpose of this study. Genistein is a naturally occurring substance that is found in food products such as soy and tofu, but is also an investigational drug for this study. Both drugs may be able to restore normal chloride movements in body organs and glands. We will be studying salt and water in the nose movement by a technique called nasal transepithelial potential difference (NPD).